PREFACE. 
RaARRIEeyyyy 
Wirn this volume is brought to a conclusion a series of works 
which all zoologists must acknowledge to be of primary importance 
in the history of science. The series consists of nine volumes, 
viz.:—The Catalogue of Batrachia Salientia, published in 1882; 
the Catalogue of Batrachia Gradientia, also in 1882; the Catalogue 
of Lizards, vol. i. 1885, vol. ii. 1885, vol. iii. 1887; the Catalogue 
of Chelonians, Rhynchocephalians, and Crocodiles, 1889; and the 
Catalogue of Snakes, vol. i. 1893, vol. ii. 1894, and vol. iii. 1896. 
These works are not only catalogues in the ordinary sense of the 
largest general collections of Batrachia and Reptilia ever yet brought 
together, but are complete monographs of the groups of animals 
treated of, so far as their zoological characters, geographical distri- 
bution, and’ synonymy are concerned—descriptions being given of 
every species regarded by the author as valid, whether contained 
in the Museum or not. 
The initiative of the series is due to Dr. Giinther. It was begun 
and has been carried out almost to its close under his Keepership 
_ of the Zoological Department. 
Of the unremitting devotion of Mr. Boulenger to the task which 
has occupied him -for more than fifteen years, or of the ability and 
